Case Report Horseshoe Kidney Protection with Histidine-Tryptophan-Ketoglutarate Solution during Surgical Abdominal Aortic Aneurysm Repair Giovanni Tinelli, Simona Sica, Fabrizio Minelli, Marco Natola, Francesca De Nigris, and Yamume Tshomba, Rome, Italy Case Report: We report an unusual case of a 65-year-old male patient with horseshoe kidney, who underwent a successful open repair for an abdominal aortic aneurysm (AAA). The acces- sory renal arteries were perfused with histidine-tryptophan-ketoglutarate (HTK) solution (Custo- diolÒ; Dr. Franz-Kohler Chemie GmbH, Bensheim, Germany) during the vascular reconstruction. There were no creatinine and estimated glomerular filtration rate (eGFR) modi- fications in the postoperative time. In the literature, only two cases of Custodiol solution for kid- ney protection during aortic surgery are reported. To the best of our knowledge, this is the first case of Custodiol perfusion for horseshoe kidney protection. Discussion: The concomitant presence of horseshoe kidney and an AAA requires a specific preoperative planning. This is necessary to define the appropriate surgical procedure and strat- egy. The onset of acute kidney injury is an aspect that must always be taken into consideration during aortic surgery, even more in the case we are reporting. Indeed, despite the complexity of the kidney anatomy, the use of Custodiol solution allowed a proper maintenance of the periop- erative renal function, as shown by the postoperative levels of creatinine and eGFR. Conclusions: Preoperative planning and organ preservation are crucial in AAA open repair, especially in the presence of congenital anomalies such as horseshoe kidney. INTRODUCTION Horseshoe kidney (HSK) is the most frequent uro- logical congenital anomaly with the lower poles (or seldom the upper poles) of the two kidneys fused anterior to the aorta through an isthmus. It may consist of functional parenchymal (85%) or fibrous tissue (15%). 1 HSK occurs in 0.25% of the general population and in 0.12% of patients presenting an aortic aneurysm. 2 The most used classification for HSK is proposed by Eisendrath et al. 3 and describes five types of vascularization. Arterial renal vascular variants must be taken into consideration to pre- serve the parenchyma during the treatment of the abdominal aortic aneurysm (AAA). A written informed consent was obtained from the patient for publication of this case report and accompanying images. Conflicts of interest: none. Funding: This research did not receive any specific grant from fund- ing agencies in the public, commercial, or not-for-profit sectors. Consent: Written informed consent was obtained from the patient for publication of this case report and accompanying images. Ethical approval: The study is exempt from ethical approval in our Institution. Unit of Vascular Surgery, Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma - Universit a Cattolica del Sacro Cuore, Rome, Italy. Correspondence to: Giovanni Tinelli, MD, PhD, Unit of Vascular Surgery, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Roma - Universit a Cattolica del Sacro Cuore, Largo Agostino Gemelli 8, 00168 Rome, Italy; E-mail: giovanni.tinelli@policlinicogemelli.it Ann Vasc Surg 2019; -: 1.e1–1.e4 https://doi.org/10.1016/j.avsg.2019.08.105 Ó 2019 Elsevier Inc. All rights reserved. Manuscript received: July 20, 2019; manuscript accepted: August 24, 2019; published online: --- 1.e1